1. Field of the Invention
The present invention relates to a technique for selecting a plurality of wireless communication paths of data from a source node to a destination node.
2. Description of the Related Art
Conventionally, as a means for achieving stable data transmission between a plurality of nodes connected via wireless communication paths in which a communication state is readily changed, a method of transmitting identical data using a plurality of different communication paths is adopted.
In Japanese Patent Laid-Open No. 8-321799, a transmitting node, which has a plurality of antennas having different directions of directivities, transmits data to a receiving node by selecting a predetermined antenna via a first communication path, selects another antenna upon occurrence of a reception error to switch to a second communication path, and then transmits data.
However, in the conventional technique, a plurality of communication paths to be selected only have different directions of directivities, and how much communication paths are spatially approximate to each other is not taken into consideration. For this reason, when a plurality of communication paths to be used are spatially approximate to each other, if any obstacle appears on the way of the communication paths, the plurality of communication paths are likely to be concurrently interrupted. As a result, although the plurality of communication paths are used, data transmission reliability cannot often be improved.
In the conventional technique, since data is re-transmitted by switching the communication path at the time of occurrence of an error, a data transmission delay is not guaranteed. For this reason, when data cannot be received by re-transmission processing within a valid period, it imposes an influence on an application that requires realtimeness. For example, when temporally continuous stream data such as video data or audio data is transmitted, and the receiving side continuously plays it back, a lack of data occurs, thus posing a problem of disturbance of playback video data or interruption of playback audio data.